Ed Feser claims that the mind-body problem is something that essentially began with Descartes. But, while it’s true that the mind-body problem as is understood today began with Rene Descartes, it’s not totally accurate to say that the issue began with him. To be sure, things changed a lot when Descartes came onto the scene. But, the mind-body problem goes back to at least the days of Plato and Aristotle. Plato and Aristotle themselves did not agree with each other on the issue.
It’s true that the mind-body problem to the Ancients and Medievals was more of a problem of soul and body, nevertheless, it’s not hard to see how this is related to the mind-body problem. In addition, it’s not as if all the ancient thinkers were of the opinion that thought itself is essentially immaterial.
Nevertheless, Feser is correct to say that Descartes opened up new problems when he came up with a mechanistic metaphysical system that abandoned things like final causation. With this new system, the interaction problem was born. In addition, another problem emerged: when does the human soul get attached to the body? But, for people like Aquinas, this question makes no sense because the soul is the form of the body.